Cardiorespiratory Physiology

Question 1

What does cardiorespiratory physiology refer to

Answer 1

The transport and utilisation of oxygen

Question 2

Where does the increased oxygen demand during exercise come from

Answer 2

Increased interaction between the myosin head and actin during muscle contraction which requires energy from ATP

Question 3

What are the 3 methods of resynthesising ATP

Answer 3

Phosphagen system, glycolytic system and oxidative phosphorylation

Question 4

Which method resynthesises the most ATP

Answer 4

Oxidative phosphorylation

Question 5

What is the creatine kinase reaction

Answer 5

Phosphocreatine splits to phosphate and creatine “donating” it’s phosphate to ADP to form ATP

Question 6

How does glycolysis generate ATP

Answer 6

Glucose or glycogen is broken down, generating ATP

Question 7

How does oxidative phosphorylation generate ATP

Answer 7

Produces ATP following the breakdown of fat, carbohydrates and protein via multiple steps

Question 8

Which methods of resynthesising ATP are aerobic and anaerobic

Answer 8

Anaerobic- creatine kinase and glycolysis
Aerobic- oxidative phosphorylation

Question 9

Which method of resynthesising ATP is more sustainable and why

Answer 9

Oxidative phosphorylation as there are limited phosphocreatine stores and high rates of glycolysis are inhibited by acidosis

Question 10

Which methods of resynthesising ATP is fastest and which is slowest

Answer 10

Fastest- creatine kinase
Slowest- oxidative phosphorylation

Question 11

What would be the predominant energy system during a marathon, 5 second sprint and 15 second sprint

Answer 11

5 second- CK
15 second- glycolysis
Marathon- Oxidative phosphorylation

Question 12

What is the oxygen cascade

Answer 12

The journey of oxygen from the atmosphere to the mitochondria

Question 13

What happens to the partial pressure of oxygen as it moves down the cascade from the atmosphere to the mitochondria and why

Answer 13

Reduces as utilised and oxygen moves down pressure gradient

Question 14

How is oxygen delivery to the mitochondria increased during exercise

Answer 14

Increased ventilation (TD xBR), increased cardiac output (SV x HR) and redistribution of of blood flow to meet metabolic demand of skeletal muscles

Question 15

What is arterial-venous difference

Answer 15

How much oxygen is in venous blood after extraction from the arteries

Question 16

How is arterial-venous difference calculated

Answer 16

The difference between oxygen concentration of the blood in the arteries and in the veins after extraction

Question 17

Why does oxygen pressure decrease in tissues during exercise

Answer 17

Increased metabolic demand so more used

Question 18

What happens to arterial-venous difference during exercise and why

Answer 18

Increases as more oxygen extracted so lower concentration of oxygen left in venous blood

Question 19

Why is more oxygen extracted during exercise from arterial blood

Answer 19

Greater gradient between blood and tissue due to increased demand and utilisation for muscle contraction

Question 20

What is fick’s equation

Answer 20

VO2= cardiac output x arterial-venous difference

Question 21

Why is the initial increase of oxygen consumption gradual when exercise onsets

Answer 21

As it can take time for the oxygen uptake to meet demand, resulting in an oxygen deficit, therefore anaerobic mechanism. (Creatine kinase and glycolysis) are used during this time

Question 22

What is VO2max

Answer 22

The maximal oxygen uptake as there is a limitation in the transport and utilisation of O2 despite increasing workload

Question 23

What the determinants of VO2max

Answer 23

Any step along the oxygen cascade could be involved (pulmonary ventilation , haemoglobin concentration, blood volume and cardiac output, peripheral blood flow/ distribution and aerobic metabolism)

Question 24

Which is the believed primary factor limiting VO2 max

Answer 24

Cardiac output

Question 25

What is the difference between a maximal and submaximal VO2max test

Answer 25

Maximal is the gold standard, lab based test that directly determines VO2 max, submaximal estimates VO2 max by using a predetermined endpoint so may be more suited to injured or vulnerable populations as fewer risks

Question 26

What are the external factors affecting VO2 max

Answer 26

Mode of exercise, state of training, sex, age, body size and composition

Question 27

Why is a plateau not always seen when measuring VO2max

Answer 27

Relies on individual to exercise or true exhaustion